Synthesis of Novel Derivatives of Imidazo[2,1-c][1,2,4]Triazine from Biologically Active 4-Arylidene-2-Hydrazino-1-Phenyl-1H-Imidazol-5(4H)-Ones and Evaluation of their Antimicrobial Activity

4-Arylidene-2-hydrazino-1-phenyl-1H-imidazolin-5(4H)-ones were synthesised and used as key intermediates for the synthesis of novel imidazo[2,1-c][1,2,4]triazine derivatives. The new imidazo[2,1-c][1,2,4]triazine derivatives were obtained via the reaction of the hydrazino derivatives with pyruvic acid, chloroacetyl chloride and phenacyl bromide derivatives respectively. Structures of the newly synthesised compounds were confirmed using spectral data as well as elemental analysis. Seven compounds were evaluated for their antimicrobial activity with minimum inhibitory concentration (MIC) values against several reference strains of bacteria and fungi, with ampicillin, gentamicin and amphotericin B used as comparison drugs. It was observed that most of the evaluated compounds showed high antibacterial as well as antifungal activities. 6-(4-Chlorobenzylidene)-4-(4-methylphenyl)-8-phenyl-6,8-dihydroimidazo-[2,1-c][1,2,4] triazin-7(2H)-one was the most potent compound with high inhibition zones and low MIC values.